This invention relates to a fluid container having a plurality of container members as packing material, and more particularly, to a method and apparatus which is capable of easily inflating the fluid container and firmly sealing the fluid container to prevent reverse flows of fluid from the plurality of separate container members where each container member is not provided with a check valve.
Styroform boxes and frames have long been used as a material for packing commodity products such a TV, VCR, washing machine, refrigerator, computer, wine bottle, etc. or industrial products such as electrical parts, mechanical parts, etc. Although the styroform has a merit such as a good thermal insulation performance and light weight, it has also various demerits. For example, recycling is not possible, a large amount of soot is produced when it is burnt, flakes or chips fall off when it gets snagged because of its brittleness, an expensive mold is needed to produce it, and a large storage space such as a warehouse is necessary to store it.
Therefore, to solve such problems noted above, a new packing method using a fluid container is recently proposed. The fluid container inflates by sealingly containing fluid such as liquid or gas therein. The fluid container has better characteristics which can solve the problems involved in the styroform. First, because the fluid container is made of only thin sheets, it does not need a special warehouse to store it unless the container is inflated. In other words, a large number of fluid containers can be transported by a small cargo stocked in a small space. Secondly, the mold is not necessary because of its simple structure, i.e., two dimensional structure by the thin sheets. Thirdly, the fluid container does not produce chips, flakes or dust that would have an adverse effect on precision products or environment. Also, material that can be recycled can be used as thermoplastic films of the fluid container. Further, because of the advantages noted above, the fluid container can be produced with a lesser cost than that of the styroform packing.
FIG. 1 is a perspective view showing an example of structure of the fluid container in the conventional technology. The container of FIG. 1 is composed of first and second thermoplastic container films 13 and 14, and a check valve 11. Typically, each thermoplastic film is composed of three layers: for example, polyethylene, nylon and polyethylene layers which are bonded together with appropriate adhesive. The first and second thermoplastic containers are heat-sealed together around a rectangular periphery except where an inlet port is formed. Thus, one container bag is formed by sealing the edges at the bonding portion 12 such as shown in FIG. 1.
In FIG. 1, the check valve 11 is typically made of two rectangular thermoplastic valve films which are bonded together to form a fluid pipe. The fluid pipe has a tip opening and a valve body to allow the fluid such as air flowing through the fluid pipe from the tip opening but the valve body disallows the reverse flow of the fluid. More details of an example of structure and performance of the check valve are disclosed in the U.S. Pat. Nos. 5,209,264, 4,708,167 and 5,927,336.
FIGS. 2A-2B show an example of a fluid container with a plurality of container members (small bags) each having a check valve. A main purpose of having a plurality of container members is to increase the reliability as well as to limit the thickness of the fluid container when it is inflated. Even if one of the container members causes an air leakage for some reason, the fluid container can still function as a cushion of package because other container members work properly. In order to achieve this purpose, each container member has to independently maintain its inflated state from the other.
Referring to FIG. 2A, the fluid container is made of first and second thermoplastic container films (FIG. 1) which are bonded together around a rectangular periphery and further bonded together at a boundary of each container member (bonded portion 12) so that a guide tube 21 and a plurality of elongated container members 22 are created. When the first and second thermoplastic container films are bonded together at the bonded portions 12, as shown by the hatching in FIG. 2A, a check-valve 11 is also embedded in each inlet port of each container member 22 to make each container member independent. The inlet port 24 of the fluid container is used when filling a fluid, typically air, to each elongated container member 22 from an air compressor and the like.
FIG. 2B shows an example of fluid container with a plurality of elongated container members each having a check valve. The fluid container of FIG. 2B is inflated by filling the fluid. First, each elongated container member 22 is filled with the fluid such as air from the inlet port 24 through the guide tube 21 and each check valve 11. Considering variations in environmental temperature, filling the fluid is typically stopped when the container member is inflated at about 90% of its full inflation rate. After filling the fluid, the inflation of each member is maintained because each check valve 11 of the container member prevents the reverse flow. Typically, the fluid supplier, such as an air compressor has a gage to always monitor the supplied fluid (air) pressure, and automatically stops supplying the air to the inlet port 24 of the fluid container when the pressure reaches a predetermined value.
As described in the foregoing, the fluid container using check valves is suitable for packing a product and is advantageous over the styroform. Thus, it can be used as a package material for any commodity or industrial products. Because the size of the fluid container is very small if the fluid is not filled in, it is easy to transport and it does not need a large space such as a warehouse to store it. The fluid container has a further advantage of its flexibility, for example, by gradually filling the fluid, it can become any shape needed to match a gap shape between a product and a package frame. In general, the overall cost of the fluid container is lower than that of the styroform because of the less cost for transportation and/or storage. However, as for the fluid container with multiple container members each having a check valve, the cost of the check valves accounts a high percentage of the total cost of the fluid container. Therefore, there is a need to reduce the cost of the check valves in the fluid container.
It is, therefore, an object of the present invention to provide a new structure of a fluid container having a plurality of small container members which can significantly reduce the overall cost.
It is another object of the present invention to provide a fluid container having a plurality of small air bags where the small air bags are air-tightly sealed without using check valves, thereby reducing the cost.
It is a further object of the present invention to provide a method and apparatus for easily and effectively sealing a plurality of container members of the fluid container after filling the fluid therein.
It is a further object of the present invention to provide a fluid container which can be repeatedly used by easily removing the clamp member and releasing the fluid from the fluid container.
It is a further object of the present invention to provide a heat-sealing method to prevent the reverse flow from each container member.
More specifically, the fluid container for sealingly containing a fluid of the present invention is comprised of: first and second thermoplastic container films juxtaposed with each other where predetermined portions of the first and second thermoplastic container films are bonded, thereby creating a guide passage, a plurality of container members, and narrow passages connecting the guide passage and the container members; and a check-valve formed at an input of the guide passage for allowing a fluid flow of only one predetermined direction. A fluid is introduced through the input of the guide passage, the check-valve, and the narrow passages to the container members, thereby inflating the container members. The narrow passages are sealed after the inflation of the container members.
In one embodiment, the narrow passages are sealed by a clamp member having a set of a clamp rod and a receptacle made of flexible material, and the clamp member clamps the narrow passages between the receptacle and the clamp rod by positioning the narrow passages on the receptacle and pressing the clamp rod in the receptacle. The clamp rod has an outer diameter which is substantially the same or smaller than an inner diameter of the receptacle, and the receptacle has an opening which is slightly smaller than the outer diameter of the clamp rod, thereby locking the clamp rod when the clamp rod is pressed in the receptacle.
In another embodiment, the narrow passages are sealed by a clamp member having two sets of a clamp rod and a receptacle made of flexible material, and the clamp member clamps the narrow passages between the receptacles and the clamp rods by positioning the narrow passages on the receptacles and pressing the clamp rods in the receptacles. In each set of the clamp rod and receptacle, the clamp rod has an outer diameter which is substantially the same or smaller than an inner diameter of the receptacle, and the receptacle has an opening which is slightly smaller than the outer diameter of the corresponding clamp rod, thereby locking the clamp rod when the clamp rod is pressed in the receptacle. The clamp member further includes a bulge between the two receptacles. The bulge is protruded in a direction opposite to an inner projection of each receptacle, thereby increasing an sealing effect when the clamp rods are pressed in the corresponding receptacles.
Another aspect of the present invention is a method of producing a fluid container which is comprised of the steps of: providing first and second thermoplastic container films juxtaposed with each other; bonding the predetermined portions of the first and second thermoplastic container films, thereby creating a guide passage, a plurality of container members, and narrow passages connecting the guide passage and the container members; forming a check-valve between the first and second thermoplastic container films at an inlet of the fluid container: and inflating the plurality of container members by introducing a fluid through the guide passage, the check-valve, and the narrow passages to the container members; and air-tightly sealing the narrow passages after the inflation of the container members.
According to the present invention, the sealing method and apparatus of the present invention enables a user to quickly inflate the fluid container and easily make each container element independent from one another by clamping or heat-sealing the narrow passages connected to the corresponding container members. If the clamping member is used, the fluid container can be used repeatedly. Further, as a result of reducing the number of check-valves used in the fluid container, the cost for producing the container is substantially reduced. If the heat sealing method is used, the single check valve makes the process easy although the container itself is non-reusable. This feature is also effective in reducing the total production cost of the container.